Countersink



Dec; 3, 1940. c EVELETH 2,223,435

) COUNTERS INK Filed Oct. 16, 1939 G'flZEveZeZiZ/ INVENTOR.

ATTORNEYS.

Patented Dec. 3, 1940 UNITED STATES PATENT OFFICE COUNTERSINK ClarenceM. Eveleth, River Forest, Ill.

Application October 16, 1939, Serial No. 299,747

' 4 Claims. (Cl. -123) This invention relates to a tool comprising astop and a countersink member journaled in the stop, the stop limitingthe amount that the countersinkilng member enters the .material. Thepresent invention aims to provide novel means whereby the stop will beprevented from marring finely finished surfaces.

It'is within the province of the disclosure to improve generally and toenhance the utility of devices of that type to which the presentinvention appertains.-

With the above and other objects in view, which will appear as thedescription proceeds, the invention resides in the combination andanrangement of parts and in the details of construction hereinafterdescribed and claimed, it being understood that changes in the preciseembodiment of the invention herein disclosed, may be made within thescope of what is claimed, without departing from the spirit of theinvention.

In the drawing:

Fig. 1 shows in elevation, a device constructed in accordance with theinvention, parts being broken away;

Fig. 2 is a bottom plan;

Figs. 3, 4 and 5 are diagrammaticelevations illustrating the operatingof the device which characterizes this application.

The numeral I marks a tubular casing provided at its lower end with afoot 2 whereon a sleeve 3 is secured by threading, the sleeve beingprovided at its lower end with an inwardly extended, annular flange 4.The numeral 5 designates a tubular stop, having a head 6 receivedbetween the flange 4 of the sleeve 3 and the foot 2 of the casing I, theconstruction being such that there can be relative movement between thecasing and the stop, so far as rotation is concerned. I v

The numeral I marksa countersink bit extended through the casing I andthe stop 5, the bit having a working end 8. The countersink bit I isthreaded at 9 into the casing I, for adjustment, to determine the amountthat the working end 8 of the bit projects downwardly beyond thelowerend of the stop 5, and to determine the depth of the countersink. Afterthe countersink bit I has been adjusted longitudinally with respect tothe casing I, the countersink bit is held in its adjusted position, bymeans of a jamb nut Ill engaged with the threads 9 of thecountersink bitand engaging the upper end of the casing I. The part I I is a knurledcollar formed on the casing I, whereby the casing can be held againstrotation whilst the jamnut I0 is being tightened up.

After the desired longitudinal adjustment of the countersink bit I hasbeen attained, and the jamb nut Ill set against the end of the casing I,

the casing I and the bit 'I turn as one piece.

Grossly considered, the device as thus far described comprises acountersink tool, including both the casing I and the bit I, and atubular stop, to wit, the part 5, the stop and the countersink toolbeing connected together for relative rotation.

Generally stated, the countersink tool, including the bit I and thecasing I, is rotated and the working end B of the bit forms acountersink in the material. The depth of the countersink is determinedwhen the lower end of the stop 5 comes into contact with the material.Such a combination of parts, and the resulting operation, are reasonablysatisfactory if rough material is being countersunk. If, however, afinely finished or polished material is being countersunk, it will bedamaged or marred by contact with the lower end of, the stop 5. Thisinvention aims to provide a simple but effective means whereby such acontingency will be avoided.

The stop 5 is provided at its lower end with circumferentially spacedfingers I2. In the lower end of each finger I2, and at one side thereof,a rectangular recess I4 is formed. A bore I5 in the finger I2 leadsupwardly from the lower end of the finger, past the recess, A cushion I6is secured in the bore. I5, and, preferably, is a cylindrical rubberplug. The plug I5 is long enough so that inits normal condition, itprojects downwardly below the lower end of the finger I2, as Fig. 3 willshow. The upper wall of the recess I4 is rounded, as shown at IT. Thisis done to the end that when the lower end of the plug I5 is flexedlaterally, as in Figs. 4 and 5, the plug will not be cut. In the upperwall of the recess 4, a circumferentially extended groove I8 i formed,the groove being shaped to correspond. with the cross sectionof the plugI6.

In practical operation, the countersinking tool 'I-I'is rotated, and theworking end 8 of the countersink bit I forms a. countersink in thematerial. When the finger I2 is rotated in the direction of the arrow Ain Fig. 3,'the lower end of the plug I6 comes into contact with thematerial. The problem presented at this stage is to stop the rotation ofthe member 5, under the drag of the'countersinking tool. That is done bypressing the tool down, as shown by the arrow B in Fig. 4, until thelower end of the plug it is 55 brought into close frictional contactwith the work. .The lower end 01 the plug it retires into the recess l4,and is held against lateral swingingmovement, because the lower part oi.the plug is received in the groove 18.

The rotation of the stop 5 now has been terminated, the parts being inthe position of Fig. 4, but that is not enough. The tool must be presseddownwardly, in the direction of the arrow C in Fig. 5, until the lowerend of the finger l2 comes into contact with the work. That contactdetermines positively, the depth of the countersink formed by theworking end 8 of the bit 1. brought into contact with the work the depthof the countersink could not be determined deflnitely, because the plug16 is compressible.

The recess l4 exercises two functions. It provides a space into whichthe flexed lower end of the plug l6 can retire, as in ,Fig. 4. Moreover,since the lower end of the'plug It does not have to be compressedthroughout its entire cross section, it is not difllcult to bring 'thefinger I2 claimed is:

1. In a device of the class described, a rigid material-engaging stophaving a bore at its lower end, a countersink tool journaled in thestop,

and a compressible, material-engaging cushion carried by the bore insaid stop and projecting If the lower end of the finger l2 were notbelow the lower end of the stop, the stop being provided at its lowerend with a. recess leading into said here and into which the cushion canretire when flexed laterally, the depth of the recess being less thanthe diameter 01' the cushion.

2. In a device of the class described, a rigid material-engaging stophaving a bore at its lower into said bore and into which the cushion canretire when flexed laterally, the depth of the recess being less thanthe diameter of the cushion, and the stop being provided, at the upperwall of the recess, with a circumferentially extended groove, receivinga portion of the cushion.

3. In a device of the class described, a rigid 2| material-engaging stophaving a longitudinal bore and a lateral recess in its lower end, the

recess leading to the bore, a compressible, ma-

terial-engaging cushion mounted in the bore and projecting beyond thelower end of the stop, the 2:

. heightfoi' the recess being less than-the diameter or the cushion, thecushion being laterally flexible to enter the recess, the stop beingrounded at the place 01'- juncture between the, recess and the bore, toprevent the cushion from being cut whenflexed, and a countersink tooljouma-led in the stop and extended downwardly below the' stop. I 4. Adevice a circumferentially extended groove, located in the upper wall ofthe recess, and shaped to receive the flexed cushion.

of the class described, constructed as set forth in claimxli and whereinthe stop has

